Means for regulating a steam turbine



1934- .1" Y. DAHLSTRAND MEANS FOR REGULATING A STEAM TURBINE Filed Jan.23, 1933 4 Sheets-Sheet ATTORNEY Dec. 25, 1934. v Y A AND 1,985,404

MEANS FOR REGULATING A STEAM TURBINE 4 Sheets-Sheet 2 Filed Jan. 25,1933 Y fl iw ATTORNEY Dec. 25, 1934- J. Y.-I DAHLSTRAND 1,935,404

' MEANS FOR REGULATING A STEAM TURBINE Filed Jan. 23, 1935 4 SheetsSheet5 P3 P4 P5 P6 75 INVENTOR 1 %Y 8 B 7M 4 57 15 ATTORNEY Dec. 25, 1934.

J. Y. DAHLSTRAND MEANS FOR REGULATING A STEAM TURBINE Filed Jan. 23,1935 4 Sheets-Sheet 4 M w W a g 3% w m M al W V B M\ l /\v| w 3, mam 4:p i H RY N3 v Sh 1 m3 3 e3 v2 mm 9% m LE m mum w n .QS.

WW H8 3 Nun mi E @3 wow a Q N. NH \QN NNH 3N EH v H @NH NH m3 Hm QPatented Dec. 25, 1934 UNITED STATES MEANS FOR REGULATING A STEAMTURBINE Josef Y. Dahlstrand, Burlington, Iowa, assignor to Murray IronWorks Company, Burlington, Iowa, a corporation of Iowaj ApplicationJanuary 23, 1933, Serial No. 653,047

10 Claims.

This invention relates tomeans for regulating a steam turbine of theimpulse type.

In steam turbines of the impulse type the kinetic energy of steam jetsimpinging on curved blades 5 or buckets fixed to a turbine wheel isconverted into mechanical work. The steam jets are produced by expandingsteam in nozzles which extend at an angle to the plane of rotation ofthe wheel and these nozzles have restricted throats 1O communicatingwith the steam ring or bowl of the turbine and relatively enlargedmouths opening in juxtaposition to the path of the blades on the wheel.

Turbines are often operated under varying load 15 conditions and requireregulation to compensate for the variations in the load. This'has beendone in the past by interposing a governing valve between the supplyline and the ring of the turbine to regulate the steam flow. Such avalve creates a pressure diiierential between the steam in the supplyline and that in the ring and the valve throttles the steam with aresultant waste'of British thermal units. Poppet valves have also beenemployed to regulate turbines but these valves also throttle the steam.

The salient object of my invention is to regulate theoperation of aturbine without creating a pressure difierential between the steam inthe supply line and that in the ring of the turbine 30 to thereby avoidthrottling the steam and the resultant waste of British thermal units.

Turbines are usually-rated to be operated at a given speed under adeterminedring pressure and under these conditions the highestefficiency is attained. If a throttling governing valve is employed andthere is a material reductionof the load on the turbine, the governingvalve so operates that the ring pressure in the turbine is materiallyreduced. The nozzles are divergent, this being essential to expand thesteam'below fiftyeight percent of the initial pressure. To provide adivergent nozzle, the area of the throat is made less than the area ofthe mouth and the divergence or taper of the nozzle, known as theexpansion ratio, is a function of the ratio be tween the ring pressureand the stage back pressure in the turbine. Hence, when the ringpressure is materially reduced, the steam consumption greatly increasesand the efficiency of the turbine is reduced. Moreover, calculation ofthe expansion ratio of a particular set of nozzles is partially based onthe stage back pressure. As the load on the turbines lightens, the stageback pressure lessens 4 and it is beneficial to vary the expansion ratioto compensate for a reduction in back pressure. However, nozzles may beunder-expanded in an appreciable amount without affecting theireificiency but over-expansion of the nozzles materially affects theefiiciency thereof.

Therefore, still another object of my invention is to provide a turbinewherein the expansion ratio of the nozzles may be adjusted to affordeficient operation under various operating conditions including amaterial reduction in stage back pressure. The power developed by aturbine is proportionate to the quantity of steam. admitted and hence,when the load on the turbine is materially reduced, it is advantageousto reduce the steam admission and this may be done by reducing theaggregate nozzle area. 1

Another object is to regulate'theoperation of a turbine by controllingthe steam flow through the nozzles without reducingthe ring pressure sothat maximum efiiciency may be maintained and an ancillary object is tovary the aggregate nozzle area of the turbine proportionately to theload.

A turbine'is often arranged so that steam may be withdrawn therefrom atone or more stages in order that steam'at' different temperatures andpressures may be supplied to appliances such as cooking vats and thelike, and a turbine so equipped is known as a bleeder turbine.Heretofore, a throttling'valve has been provided'to regulate the bleedfroma turbine but the use of such a valve is subject to manydisadvantages. Hence, a further object of this invention is to provide anovel bleeder turbine in which the steam withdrawal is controlled byvarying the area of the outlet nozzles from the bleeder chamber.

Still further objects of the invention are provide a turbine havingnovel reamed nozzles into which tapered adjustable needle valves areextended to aiford variation of the nozzle area and expansion ratio; to.automatically actuate the needle valves proportionately to variations inoperating conditions; to control a plurality of nozzles so that widevariations in operating conditions may be accommodated; to provide anexpeditious adjustment so that the same'turbine may be used underdifferent operating conditions such as variations in initial steampressure, load, andspeed; and to provide a novel turbine control ofsimple and economical construction and efficient and positive operation.

Selected embodiments of the invention are illustrated in theaccompanyingdrawings wherein Fig-l isa plan view Fig. '7 is a vertical sectionalview taken sub-,

stantially on the line 7'7 on Fig. 4;

Fig. 8 is a vertical sectional view takensubstantially on the line 88 onFig. 1; and

' Fig. 9 is a fragmentary vertical sectional view taken substantially onthe line;9- 9 on Fig.2.

In the accompanying drawings, 10 indicates a base supporting a turbinecasing 11 having end plates 12 and 13 providing bearings in :which aturbine shaft 14 is journaled. A ring or bowl 15 is provided in the endplate 12 and this end plate includes a wall :16 in-which the nozzles 17are provided. "The first stage wheel 18 of the turbine isijfast on;theshaft 14 adjacent 'thewall 16 and thebuckets or blades on the peripheryof this wheel are arranged in two rows 19 and 20. A diaphragm 21 iscarried by the casing '11 and is interposed between the rows of buckets19 and and has a rowof buckets 22 thereon. An inlet 23 has a valve 24therein and leads to the ring 15. Steam flows through the inletinto*thering and through the nozzles 17 whichextend at an angle to the planeof rotation'of the wheel 18 and the jets of steam emitted from thesenozzles first impinge on the buckets in the row 19, then on the bucketsin the row '22, and thenon the buckets :in the row 20 from ,whence thesteam flows into the bleeder chamber 25 when the turbine is equipped.withsuch .achamber behind the first stage therein. Ifnobleeder chamberis provided at this position, the steam flows into the second stage orto the exhaust as the case may ,be.

The nozzles l'l are of the .kind described'and claimed in my Patent No.1,561,835, patentedNov b r .7, .1 5..a ,d1are s aigh leaniedhql In orderto provide for efficient expansion of st am in the nozzles, whi h iusual p remplished by tapering the nozzles, tapered ;ne e d le valves 26are extended into the th-rolats -of rthe nozzles and these taperedneedle ivalves ,may ,be used to vary the aggregate nczzle areaas will beexplained. In the illustrated embodimentof the invention, I show sevennozzles but a greater or less number might be provided depending uponthe size of the turbine, the horsepower to be developed, the speed-ofoperatiomand the like.

The va1ve24 ispr e f h yo tb wfi rdine unobstructed steam passageand;henc e it does not have any throttling effect andsinceithe inlet 23leadsdirectly to the ring or bowl and asthe intakes of the nozzlescommunicate with the ring, it is clear thatthe pressure at the intakesofthe nozzles is line pressure. I

The seven nozzles provided in the illustrated turbine are arranged sideby side and so far as constructional features are concerned, they areidentical. The needle valve for each nozzle includes a stem 27 that isextended through a bore in thebody 28 mounted in a-tapped-opening intheplate 12. Ahousing-29 is screwthreadedonto the end .of each body 28 andeach has a chamber 30 therein in which packing nuts- 31 and 3 2 areprovided. The stem 2? of each needlevalve extends vinto the housing ;,29through the packing nuts 31 and 32 and suitable packing engaged :by

these nuts so that when the nuts are tightened the packing is tightlyclamped about the stems 27 to prevent leakage thereby. A cylinder 33 isprovided in each housing and a piston 34 is reciprocably mounted in eachcylinder. The outer ends of the stems 2'7 are respectively connected tothe pistons. Chambers W arethus defined between the faces of the pistonstowhichthe stems are connected and the adjacent ends of the cylinders.

Pins 35 extend axially from each piston 34 opposite to but in alinementwith the stem 27 con nected to the piston and these pins project intobores in the caps 36 secured to the outer ends of thehQusings 29. Otherchambers X are thus ,QGfiIIQd'bBUWBED the faces of the pistons to which.the' pins are connected and the adjacent ends of the cylinders. Tubes37 are connected at the outer-ends of'each of the caps 36 and the boresin the tubes communicate with the bores in the caps. A chamber 38, Fig.3, is provided in the base 10 atthe foreward end thereof. A tubularhousing 39 projects through an opening 40 in the upperiwallofthe chamberand has a body 41 at the lower end thereof in which a gear pump 42isprovided. A housing43 is securedto the upper end of the housing 39 andthe shaft 14 extends thereinto. A gear 44 is fast on the shaft 14 in thehousing 43 and meshes with a gear 45 fast on the. vertical shaft 46journaled in suitable bearings provided in the housing 43. A coupling 47interconnects the shaft 46 with the shaft 48 of the gearpump 42 so thatwhen the shaft46 is 1'0- tated with the shaft 14 the gear pump isoperated. 'Thechamber 38 serves as an oil reservoir and the gear pumpwithdraws oil from this reservoir and'forces the oil under. pressurethrough anoutlet tooperate certain devices as will be explainedhereinafter.

Another housing 49 is mounted on the upper end of the housing .43 andencloses a weight-actuated governor 50,0f the usual construction andwhich includes a sleeve .51 disposed about the shaft 46. A spring52isdisposed about the sleeve 51 andacts thereon ito urge the Weights ofthe governor towardthe shaft 46. Alever 53'has a link 54 .connected .to.one {end thereof and ,this link is pivotally connectedtoa lug55in'thehousing 49. The sleeve 51 is connccted,to the lever 53 adjacentthe end thereof connected to the link 54. Linksfidare pivotally-mountedon a rod 5'? carried by-the forkedend of the lever 53 opposite the endthereof connectedtothe link 54. One end of a spring ;5 8,is connectedztothe lever 53 intermediate the lrodfi'? and the connection thereof to thesleeve 5gl. -Theother end ,of the spring 58 is connectedto an adjustingdevicemounted in the top plateof :the housing 49 and by means ofwhich-thetensionon, the lever 53 may tie-varied.

Theneedlewalves are controlled bythe governor 59 and preferablythesevalves are so arranged that each can beoperated independently. Thismay be accomplished in a variety of waysand-in the illustratedembodiment of the invention I have shown pressure-actuated means forthis purpose. I;h e pressure-actuated means provided for each-cf theneedle valves includes a cylinder havinga;piston--thereinand a pilotvalve for controlling movement of the piston in the cylinder. The pilotvalves ,are actuated by thegovernor 50 and to this end the free ends ofthe links 56 are connected-to ;a rod-61. Seven bell cranks 6c aremounted at spaced intervalson the rod 61. The arms 62 of each of thebell cranks are pivotally connectedat 63 to sleeves 164 adj ustablymounted Q1 r99 5 6. ertend dthroueh pa in nu s and the plungers in theirreciprocation.

in-therblock B. Conduits 89 are connected to the suitable packingintoithe cylinders 66 whereat they are respectively connected to thepistons 67. The cylinders 66 are arranged in side-by-side relation andin-the illustrated embodiment are formed in a. block B, Fig. 6. Achamber Y is defined in each cylindertfi-intermediate the face of thepiston 67 to whichthe rod is connected and the adjacent end of thecylinder. Pins 68 extend from the pistons 67 opposite to and inalinement with the rods 65 connected to the pistons and these pinsproject into sleeves 69 leading from the cylinders 66. A'chamber Z isdefined in each cylinder 66" intermediate the face of the piston 67 towhich the pin 68 is connected and the adjacent end of the cylinder. Thetubes 37' which are respectively connected to the caps 36 arerespectively connected to the sleeves 59 and the tube leading from thefirstof theneedle valves is connected to the first of the sleeves 69while the tube leading fromthe second of the needle valves is connectedto the second of the sleeves 69 and so on in succession. The respectivetubes 37 are entirely filled with balls '70 so that the space betweeneach set of pins 35 and 68 is entirely filled and preferably these ballsoperate in a light lubricating oil to insure free movement.

Seven'pilot valves are provided in the block B and these valvesarerespectively alined with the cylinders 66. Each pilot valve includes aplunger P and these plungers are respectively connected to the arms '71of the bell cranks 60 by pins 72 (Figs. 3and 5) disposed in slots '73 inthe blocks 74 adjustably mounted on therods 75 respectively connectedtothe upper ends of the plungers P. Each of the plungers isrecipro cal ina sleeve '77 and these sleeves are fitted in vertical bores 73 in theblock B. Passages '79 in the block B interconnect the respective pilotvalves and thechambers Y in the cylinders 66 respectively alined withthe valves. The ends of these passages outwardly of the pilot valves areclosed by plugs 80. Ports '79 are provided in the sleeves '77 inalineinent with the passages 79. A passage 81 is drilled through theblock B and the sleeves 77 and interconnects the various sleeves. Anintake pipe. 82 is connected at one end of the passage 81 and this pipeis likewise connected to the outlet ofthe pump 42. An outlet pipe 83 isconnected to the other end of the passage 81 and leads to thechamberiifi. The ports '79 are disposed in the sleeves 7'! above thepassage 81. Collars 84 are provided on I the plungers P which slide onthe sleeves 7'? to open and close the ports '79. Enlarged portions 85are provided at theupper ends of the plungers P which also slide on thesleeves 7'7 and guide The pertions of the plungers P intermediate thecollars 84 and the enlarged portions 85 are relieved. When the collars84 are positioned in the sleeves to be disposed below the passage 81,this passage and the ports '79 are in communication due to the relief ofthe plungers. be moved into such a position that communication betweenthe passage 81 and the ports '79 is shutoff. 1

Collars 86 are provided at the lower ends of the plungers P and theportions of the plungers inter-- mediate the collars 84 and 86 arerelieved so that when the collars 84 arepositioned in the sleeves to bedisposed'above the passage 83.,oil flowing through said passage may flowpast the relieved portions of the plungers P. Ports 87 areprovidedadjacent the lower ends of the sleeves 7'7 and respectivelycommunicate with passages 88 The collars 84 may respective passages 88and lead to the housings 29 to communicate with the chambers W therein.The collars-fifi controlflow of oil through the ports 8'? and when theplungers P are so disposedthat the collars 86 open the ports 87 forcommunication with the relieved portions of the plungers P intermediatethe collars 84 and 86, oil flows to the conduits 89 into the chambers W.The plungers 1? may be so positioned that the collars 88 close oii theports 87 from communication with the passage 81. Likewise the plungersmay be so disposed that the collars 86 open communication between theports 87 and the open lower ends of the sleeves 77.

A chamber 91 is provided at the bottom or" the block B and the bores '78and sleeves 77 open into this chamber. A transverse passage 92 in theblock B establishes communication between the chambers Z of thecylinders 66 and the cham ber 91 so that any oil leaking past thepistons 67 flows into said chamber. Each plunger P includes a bore 81which extends axially therethrough from the lower end thereof to'a portlocated in the relieved portion of the plunger P intermediate the collar34 thereon and the enlarged portion thereof. The collars s4 controlcommunication between the ports '79 and the ports 80 and, whencommunication is opened between the ports 79' and the ports 80, oil mayflow through the bore 81 into the chamber 91. An, outlet pipe 93leads-from the chamber 91 to thereservoir 38. A drain pipe leads fromeach of the chambers X in the housings 29 to the reservoir 38 so thatany oil seeping past the pistons 34 may be returned to the reservoir. I

The nozzles are so calculated that when all are open sufiicient steamflows ,therethrough' to efficiently operate'theturbine under a loadgreater than its rated, capacity. In this turbine, wherein seven needlevalves are provided, and when it is operated under a load ofseventy-five percent of its rated capacity, which obviously requiresless steam than when the turbine is operated under a load of its ratedcapacity or more than its rated capacity, some of the nozzles may beclosedoff. By Way of example, when the turbine is operat ing under aseventy-five percent load, two of the needle valves are tightly seatedon the intakes of their nozzles so that no steam flows through thesenozzles. When the load is decreased, say for example to twenty-fivepercent of the rated capacity of the turbinejiour of the needle valvesare tightly seated on the intakes of their nozzles to close off steamflow vtherethrough. Thus, by seating or unseating the needle valves fromtheir nozzles, the aggregate nozzle area may be varied and I vary thisaggregate nozzle area proportionately to the load on the turbine. Thespeed of the turbine is determined by the load thereon for it operatesat slightly different speeds at different loads and hence changes inload affect the governor fill-and since the pilot valves are controlledby the governor 50 and as these. pilot valves, in turn, control themeans regulating the needle valves, I am enabled to control the steamfiowfro'in the ring or bowl into the first stage proportionately to theload on the turbine.

As stated, when the turbine is operating under a load of seventy-fivepercent of its rated ca- F pacity, two of the needle valves are seatedon the intakes their nozzles. Underthis condition, four of the nozzlesare opened fully and one is used for regulating purposes, as will beexplained. This is accomplished by setting the .plungers P at differentpositions in the sleeves '77. Thus, the plunger P which regulates themovement of the piston 6'7 in the cylinder 66.con-, nected through atube 37 to the first of the needle valves, is so positioned that whenthe turbine is operating in the manner just described, the collar 86thereon is disposed below its cooperating port 87 and therefore oilflows from the passage 81 through the port 87, passage 81 and conduit 89into the chamber W of the housing 29 of ;the first needle valve and thepressure of this oil acts on the piston 34 to force it against the outerend or the cylinder 33 as illustrated in Fig. '7. At this same time thecollar 84 is so positioned that communication is opened between the port79 and the port 80' and therefore oil pressure in the chamber Y may berelieved for oilmay flow from the chamber Y through passage 79, port'79, port 80, bore 81 into the chamber 91 to be returned to thereservoir 38. The plunger P is positioned somewhat similarly to theplunger P so that oil may flow into the chamber W in the housing 29 ofthe needle valve for the second nozzle. However, the plunger P2 is sopositioned that upon conjoint movement of the plungers P and P (theplungers all being connected to the rod 61 for such movement with therod), the collars 86 and 84 on the plunger P will close of"? oil flow inthe above described man ner before the collars as and 86 on the plungerP so act. Inasmuch as four nozzles are to be wide open when the turbineis operating at seventy-five percent of its rated capacity, the plungersP and P are also so positioned that oil will flow to the chambers W inthe housings 29 for the needle valves of the third and fourth nozzles.However, the plungers P and P' are respectively so positioned relativeto the plungers P and P that the collars 84 and 86 on'the plunger P willclose off the foregoing communication upon'conjoint movement of theplungers prior to the time the collars 84 and 86 on the plunger P closeoff communication, and likewise the collars 8 1 and 86 on the plunger Pare positioned to close off communication before the collars 84 and 86on the plunger P so close off communication. The plunger P is also setrelative to the plunger P so that the collars 84 and 86 thereon willclose off the foregoing communication prior to the time the collars 84and 86 on the plunger P so operate. However, when the machine isoperating at seventy-five percent of its rated capacity, the collar 84on the plunger P is arranged in the manner shown in Fig. 3, that is tosay, it is disposed directly over the port '79 so that communicationthrough this port is shut off. Likewise, the collar 86 on the plunger Pis disposed over the port 87 so that communication through this port isshut off. The plunger P is so set that the collars es and 86'thereon areadvanced beyond the position or" the collars 84.- and 86 on the plungerP Hence, since the collars 84 and 86 are disposed directly over theoutlet of the passage "19 and the port 87, it is clear that the collars84 and 86 on the. plunger P are arranged in an opposite manner to thecollars 84 and 86 on the plunger P Hence, the collar 84 on the plunger Pis so disposed that communication is opened between the passage 81 andthe port 79 and hence'oil flows from the passage 81, past the relievedportion of the plunger, through port 79', and through the passage '79into the chamber Y of the cylinder alined with the pilot valve includingthe plunger P and the pressure of the oil-acts on the piston 67 to forcethe same toward the chamber Z. At this same time :the collar =86 is sodisposed that communication is opened between the port 87 and thechamber 91. The oil pressure on the :piston'fi'? tends to force the pin68 through the sleeve 69 and this movement is transmitted through theballs to the pin 35 connected to thepiston 34 in the cylinder 33 of thehousing 29 for the valve of the sixth nozzle and this urges the piston'34 toward the chamber W. At this time oil is free to flow from thechamber W through the conduit 89, passage 81, port 87 into chamber 91and therefore the oil pressure on the piston 67 so acts that the needlevalve 26 for the sixth nozzle is urged into seating engagement with theintake of the nozzles and closes off this nozzle. The collars 84 and 86on the plunger 1 are positioned similarly to the collars '84 and 860mthe plunger P but these collars'are so arranged that communication tothe chamber Y of the seventh cylinder will be established prior to thetime communication is established to the chamber Y of the sixth cylinderand likewise communication will be opened from the chamber W of theseventh needle valve prior to the time communication is opened from ithe chamber W of'the sixthineedle valve. Hence, when the machine isoperating at seventy-five percent of its rated capacity, four'needlevalves are held in wide'open position and two are closed.

The other needle valve is so arranged that it can fluctuate tocompensate for slight variations in the speed of the turbine. When theturbine is loaded to seventy-five percent of its rated capacity, itoperates at a predetermined speed and the weights of the governor assumea determined position. When, however, the load on the turbine isdecreased, and thesteam flow from the ring or bowl is to be decreased,the turbine speeds up which causes the weights of the governor 50 tomove outwardly and therefore the sleeve 51 is moved upwardly. Upwardmovement of the sleeve 51 moves the lever 53 and the links 56 upwardlyand consequently raises the rod 61. All of the plungers P are connectedto the rod 61 and hence when this rod 61 moves upwardly all of theplungers move similarly, the bell cranks fulcruming about the pivotalconnections 63. However, when the movement is slight, none of theplungers are moved suiiiciently to aifect the needle valves controlledthereby except the plunger P Since the collars on this plunger arepositioned directly over the ports '79 and 87, slight movement of theplunger P opens these ports. Hence, when, as described, the rod 61 movesupwardly, indicating an increase in speed of the turbine, which isindicative of a decrease in the load, it is essential that the steamsupply be slightly reduced in order to bring the turbine back to itsnormal speed for a seventy-five percent load. Therefore, when theplunger P moves upwardly, the collar 84 thereon moves into such aposition that communication is established between the passage 81 andthe port '79 and passage '79 leading to the fifth cylinder and thereforeadditional oil flows into the chamber Y which moves the piston 67 tomove the pin 68 through'the sleeve 69 and this movement is transmittedthrough the balls 70 to the pin 35 to move the piston 34 of the fifthneedle valve toward the chamber W and, since at this time communicationis established between the port 87 and the chamber 91, movement of thepiston 34 toward the "chamber W forces oil from the chamber W into thechamber 91. At the time the piston 67 moves in the manner justdescribed, the pin 65 is, of course, moved; This changes the position ofthe pivotal connection 63 and the fifth bell crank pivots about the rod61 which moves the arm 71 of the fifth bell crank and causes the pin '72thereon to move through the slot 73 and this forces theplunger Pdownwardly so that the collars 84 and 86 move back into position toclose off the passage 79 and the port 87. 1 Thus, the fifth needle valveis returned in the position into which it has been moved. However, sincethe fifth needle valve has been moved inwardly in. a slight amount, thesteam flow through the fifth needle valve is reduced which may besufficient to cause a decrease in the speed of the turbine. Therefore,the weights of the governor 50 are moved inwardly and the spring 52 actsto move the sleeve 51 downwardly. This moves the lever 53 and the links56 downwardly and consequently the rod 61 also moves downwardly andpivots the bell cranks 60 about the connection 63. However, thismovement will be slight and none of the plungers P willbemovedsufilciently to afiect the seating of the needle valvescontrolled there? by except the plunger P This plunger will so moveunder these conditions that the collar 84 thereon will move fromposition over the port '79 and open communication between the chamber Yand the port 80 At this same time the collar 86 opens communicationbetween the port 8'7 and the passage 81. Hence oil flows through theport 87, passage 83 and conduit. 89 into the chamber W of the fifthneedle valve and the pressure of this oil acts on the piston. 34 to movethis piston toward the chamber. X and this movement is transmittedthrough the balls 70 so that the piston 67 is urged toward the chamberY, and oil is forced from the chamber Y through thepassage 79, port 79',port 80' and bore 81' into the chamber 91. However, when the piston 67moves upwardly, the pin 65 is also moved upwardlyand the fifth bellcrank fulcrums on the rod 61 and the pin '72 moves through the slot '73to move the plunger P back into position whereat the collar 84 shuts offthe port '79 and the collar 86 closes the port 87. 1

The fifth needle valve continues to fluctuate in thismanner solongasthere are slight varia-..

tions in the turbine operating speed and the .turbine continues tooperate under-a seventy-five percent load. Howeven-when there is amaterial reduction in theload, on the turbine, say for example, when theload is reduced to twentyfive percent of the rated capacity of theturbine, there is a noticeable increase in speed of the turbine. Thiscauses the weights of the governor 50 to move outwardly which causes thesleeve'51, links 56 lever 53 and rod 61 to move upwardly and in thisinstance the movement of the rod 61 is suficiently to move the plungersP and P into positions similar to that in which the plungers P and Phave been disposed; that is to say, so that communication is establishedbetween the chambers W of the fourth and fifth needle valves and thechamber 91 and so thatcommunication is opened between the chambers Y ofthe fourth and fifth cylinders and the passage 81. There-'- fore, oilflows into these chambers Y and acts in the above described manner toseat the needle valves on the intakes of the fourth and fifth nozzles tothereby close ofi these nozzles. The foregoing movement moves theplunger P into a position similar to that shown in Fig. 3 so that thisplunger P then begins to operate in the manner in which the plunger Poperates when the turbine is operating under seventy-five percent loadcon-' ditions. The normal turbine speed for a twentyfive percent load isdifferent from that for aseventy+five percent load and thereforenotwithstanding the fact that two nozzles have been shut off entirely,the turbine will not slow down to the speed at which it was operatingbefore the foregoing change occurred. Hence, the rod 61 is disposed in aslightly difierent position and the various plungers are so disposedthat the fourth, fifth, sixth and. seventh needle valves remain closedwhereas the first and second remain open and the third needle .valvefluctuates to care for slight variations in speed.

If the machine is operating under twenty-five percent load as justdescribed and the load is increased to one hundred percent load, theturbine slows down, the. weights of the governor 50 move inwardly, andthe spring 52 acts to move the sleeve 51 downwardly and therefore thelever 53, links 56 and rod 61 move downwardly, and this movement of therod 61 is sufficient to so position the plungers that the first, second,third,

fourth and fifth needle valves are open wide while the seventh needlevalve remains closed and at this time the sixth needle valve isfluctuated in the manner in which the fifth needle valve fluctuates whenthe machine is operating under a seventy-five percent load, as describedabove. If the machine is overloaded, the rod 61 moves downwardly stillmore and the sixthneedle valve is opened wide and the seventh needlevalve then fluctuates in the manner described to care for slightvariations in turbine speed.

From the foregoing it will be apparent that I have provided anarrangement which regulates the operation of a turbine withoutthrottling the steam. The device so operates that the steam input to thefirst stage is controlled proportionately to the load on the-turbine andfurthermore the device so operates that the steam input is variedproportionately to slight variations in the-load or speed of the turbineand this regulation for slight variations in speed operates under agreat variety of load conditions; that is to say, it is effective eitherin fractional loads, normal load. or overload.

In the illustrated turbine, a bleeder chamber 25 .is provided betweenthe first and second stages. This'chamber includes a bleeder outlet 95to which a steam line 95 is connected so that steam bled from theturbine may be directed to applianoes'in which the steam is used forheating purposes and the like. As these appliances are turned on and offthe steam consumption varies which varies the pressure in the bleederline and consequently in the bleeder chamber 25.

One of the objects of this invention is to maintain a constant pressurein the bleeder line and bleeder chamber without throttling the steam andto this end nozzles 96 are provided in the wall 94 at the inner end ofthe bleeder chamber 25. The nozzles 96, whichare similar to the nozzles17, extend'at an angle to the plane of rotation of the second stagewheel 97 fast on the shaft 14 admay pass directly to the exhaust, any ofthese arrangements being in accordance with thewellunderstood practice.

In order to regulate the pressure in the chamber without throttling thesteam, needle valves 99, substantially similar to the needle valves 26,are provided'for the nozzles 96.

As the pressure in the chamber 25 falls means are provided for closingoff one or more of the nozzles 96, six nozzles being provided in theillustrated turbine. As the pressure in the chamber 25 rises, additionalnozzles are rendered operative so as to increase the steam fiow tothesecond stage which will reduce the pressure in the chamber 25.

Inasmuch as the steam flow through the'nozzles 96 is determined inaccordance with the pressure in the chamber 25 or the bleeder line,pressure responsive means are provided for controlling the operation ofthe needle valves 99. This pressure responsive means, illustrated indetail in Fig. 8, includes a body 100 secured to the turbine casing 11.A cylinder 101 is provided in the body 100 and a piston 102 isreciprocal therein. A conduit 103 leads from the pressure chamber 25 toone end of the cylinder 101 and pressure variations in the chamber 25are transmitted through this conduit to the cylinder 101 whereby theposition of the piston 102 is varied. The piston includes a shoulderedend 103 and extends into a chamher 104 in the body100 above and aboutthe cylinder 101. A spring 105 in the chamber 104 bears on theshouldered end 103 of the piston and against an adjusting nut 106. Byvarying the position of the adjusting nut 106, the tension of the spring105 may be varied which affords an adjustment for regulating theoperation of the device. A rod 107 is connected to the shouldered end103 of the piston 102 and extends out through an opening 108 in the nut106. One-end of a lever 109 is pivotally connected at 110 to a sleeve111 adjustably mounted on the rod 107. The lever 109 is connectedintermediate its ends at 112 to a sleeve 113 adjustably mounted in therod 114 which extends through a packing gland into the cylinder 115provided in the body 100 and this end of the rod is connected to apiston reciprocal in the cylinder 115. The forked end of the lever 109opposite to that connected to the sleeve 111 is pivotally connected at116 to links 117. The links 117 are pivotally connected to a rod 118. Inthe present instance, Where six nozzles and needle valves are provided,six bell cranks 120 are provided and the arms 119 of these bellcranksare pivotally connected to the rod 118. Pins 121 in the bell cranksextend into slots 122 in blocks 123 adjustably mounted on rods 124. Therods 124 are connected to the upper end portions 125 of the plungers Vof the pilot valves 126. A block 127, similar to the block B, isprovided and the valves 126 are formed in this block as are sixcylinders 127 in which pistons 133 are reciprocal. Rods 131 areconnected to the pistons 133 and extend from the cylinders throughsuitable packing glands and have sleeves adjustably mounted thereon. Thearms 128 of the bell cranks 120 are pivotally connected at 129 to thesleeves 130.

Pins 134 project from the pistons 133 opposite to and in alinement withthe rods 131 and these pins extend into sleeves 135 mounted at the lowerends of the cylinders 132. Tubes 136 are respec tively connected to thesleeves 135 and these tubes are respectively connected to caps 139provided at the outer end of the bodies 140 of the needle er chamberafter the second 'stage'or .the steam valves cooperating with the sixnozzles. The tubes 136 are filled with balls 137 which are arrangedsimilarly to the balls 70.

In operation, certain of the needle valves are arranged to be wide openand others are seated against the intakes of their nozzles and thisarrangement is such that, so long as a predetermined pressure ismaintained in the bleeder chamber '25, the needle valves remain in thisposition. One needle valve is arranged to fluctuate (in the mannerpreviously described so .as to care for .slight variations in pressure,slight variations in pressure imparting small movement to the piston 102which moves the rod 107 which, in turn, pivots the lever 109 about itsfulcrum 112. This movement istransmitted through the links 117 to therod 118 to lower the rod 118 when the pressure in the chamber 25 risesand to raise the rod 118 as the pressure falls. The plungers V arearranged in staggered relation in the same manner as the plungers P andhence, when the rod 118 moves downwardly, communication is establishedbetween the oil intake line 141 and the conduits 142 which lead .tochambers in the bodies 140 substantially similar to the chambers W. thenumber of conduits 142 connected to the intake line 141 being dependentupon the pressure, it being apparent that when oil flows through theconduits 142 the needle valves '99 are moved into .open position. Theoil intake line 141 is connected to the oil supply line 82, Fig. 3.Likewise, when the pressure drops and the rod 118 moves upwardly, theplungers V also move upwardly and said plungers close off communicationto one .or more of the conduits 142 and open communication into one ormore of the cylinders 132 to act on the pistons 133 therein to move thepins 134 through the sleeves 135 to thereby force :the'needle valvestowhich the various tubes 136 lead inwardly to seat on the intakes ofthe nozzles. 'As stated, one of the nozzles, which is always the nozzleadjacent the last wide open nozzle, fluctuates to care for slightvariations in pressure- The provision of a plurality of nozzles leadingfrom the bleeder'chamber and the provision of means for controllingsteam flow through these nozzles enables me to care for variations inpressure in the bleeder chamber without throttling the steam and, byproviding a plurality of nozzles, I'am enabled to care for widevariations in pressure. At the same time, the arrangement is such thatcompensation is made for slight variations in pressure and therefore itis possible to maintain within relatively narrow limits a desiredpressure in the bleeder chamber.

It will be apparent from the foregoing description that I have provideda method and means for regulating a turbine so that the steam input maybe kept proportionate to the load on the turbine and furthermore I amenabled to maintain the turbine speed within definite narrow limits.Moreover, the arrangement is susceptible for use in connection with ableeder chamber so that desired pressure may be maintained in thebleeder chamber and bleeder line. Since the arrange ment is such that itdirectly controls the steam flow through the nozzles, it is possible toregulate the operation of the turbine or the pressure in the bleederchamber without throttling the steam which obviously increases theefficiency of the apparatus.

In the foregoing description I have described my invention in connectionwith a steam turbine but it is to be understood that steam is used in tohold a'gene'ric sense for my invention is'adaptable for use with anyturbine employing an elastic fluid.

While I have illustrated and described selected embodiments of myinvention, it is to be under stood that'these are capable of variationand modification and 'I therefore do not wish to be limited to theprecise details set forth but desire to avail myself of such changes andalterations as fall within the purview of the following claims.

I claim:

1. In a steam turbine, a wheel having buckets thereon, a plurality ofnozzles for emitting jets of steam to the buckets on said wheel, aneedle valve for each of said nozzles and shaped to determine theexpansion ratio of the nozzle with which it cooperates when extendedinto the inlet of said nozzle and movable between closed and wide openpositions relative to said inlet and into positions intermediate theclosed and wide open positions, the position of said needle valvesrelative to the inlets of said nozzles regulating steam emission fromthe nozzles,'fiuid operated for independently eifecting movement ofthe-needle valves into closed and wide open positions and positionsintermediate the-closed and wide open positions, means for controllingop eration of the turbine proportionately to operat ing conditionsthereof and operable to selectively actuate said fluid operated means toselectively position said needle valves in closed or wide open positionsor in positions intermediate closed and Wide open positions to regulatesteam emission to said buckets, and second fluid operated meanscooperating with the first fluid operated means said needle valves inthe positions into which they are moved upon operation of the meanscontrolling operation of the turbine, said means controlling operationof the turbine in cluding pilot valves for regulating flow of fluid itothe first and second fluid operated means.

2. In a steam turbine, a wheel having buckets thereon, a plurality ofnozzles for emitting jets of steam to the buckets on said wheel, aneedle valve for each of said nozzles and shaped to determine theexpansion ratio of the nozzle with which it cooperates when extendedinto the inlet of said nozzle and movable between closed and wide openpositions relative to said inlet and into positions intermediate theclosed and wide open positions, the positions of said needle valvesrelative to the inlets of said'nozzles regulating steam emission fromthe nozzles, fiuid operated means for independently effecting-movementof the needle valves into closed and wide open p0- -sitions andpositions intermediate the closed and wide open positions, means forcontrolling operation of the turbine proportionately to operatingconditions thereof and operable to selectively actuate said fluidoperated means to selectively position said needle valves in closed orwide open positions or in positions intermediate closed and wide openpositions to regulate steam emission to said buckets, and second fluidoperated means" cooperating with the first fluid operated means to holdsaid needle valves in the positions into which they are moved uponoperation of the means controlling operation of the turbine, said meanscontrolling operation of the turbine including pilot valves forregulating flow of-fluid to the'first and second fluid operated means,and means common to said pilot valves andoperable ,upon operation ofsaid means controlling operation of the turbine to selectively controlthe flow of fluid to said first and second fluid operated means.

.' 3. In a steam turbine, a wheel having buckets thereon, a plurality ofnozzles for emitting jets of steam to the buckets on said wheel, aneedle valve for each of said nozzles and shaped to determine theexpansion ratio of the nozzle with which it cooperates when extendedinto the inlet'of said nozzle and movable between closed and wide openpositions relative to said inlet and into positions intermediatetheclosed and wide open positions, the positions of said needle valvesrelative to the inlets of said nozdle valves in the positions into whichthey are i moved upon operation of the means controlling operation ofthe turbine, said means controlling operation of the turbine includingpilot valves for regulating flow of fluid to the first and second fluidoperated means, and means to which all of said pilot valves areconnected whereby all of said pilot valves aremoved upon operation ofsaid means controlling the operation of the turbine.

4. In a steam turbine, a wheel having buckets thereon, a nozzle foremitting a jet of steam to the buckets on said wheel, a needle valve forsaid nozzle and shaped to determine the expansion ratio of the nozzlewhen extended into the inlet of said nozzle and movable between closedand wide open positions relative to said inlet and into positionsintermediate the closed and wide open positions, a cylinder, a piston insaid cylinder, said needle valve including a stem exw tended into saidcylinder and connected to said piston whereby said needle valve ismovable with said piston, means for admitting fluid to said cylinder onboth sides of saidpiston to effect movement of said piston and saidneedle valve,

and means cooperating with said piston on the side thereof opposite tothat whereat said stem is connected and adapted to retain said piston inpositions into which it ismoved by fluid adimitted into said cylinder onthe side of said piston whereat said stem is connected.

5. In a steam turbine, a wheel having buckets thereon, a nozzle foremitting a jet of steam to the buckets on said wheel, a needle-valve forsaid nozzle and shaped to determine the expansion ratio of the nozzlewhen extended into the inlet of said nozzle and movable between closedand wide open positions relative to said inlet and intopositions-intermediate the closed and wide open positions, a cylinder, apiston in said cylinder, said needle valve including a stem extendedinto said cylinder and connected to said piston whereby i said needlevalve is movable with said piston,

means for admitting fluid to said cylinder on both sides of said pistonto effect movement of said piston and said needle valve, a secondcylinder,

for transmitting the movement of one of said pistons to the other ofsaid pistons, and means fonadmittinga fluid :un-denprcssure. to: thesecond cylinder. to hold the pistonztherein againstpmovee mentiinonedirection. wherebyithe pistonto which said stem is connected may beretained in positions into which it is'm'oved by-fluid admitted into thefirst cylinder on the side of .the piston-thereinwhereat said stem isconnected;

6. lnasteamzturbine a wheel having'buckets thereon, a nozzlefor:emitting a: jet of: steam to the bucketson said wheel, .a needle: valve"ion-said nozzle and shapedto determine the expansionratio of the nozzlewhen extended intQtheiinletof said nozzle and movable between closed-andwide open' positions relative to saidinlet and into positionsintermediate the closed and wide open positions, a. cylinder, a pistonin, said cylinder, said needle-valve including a stem extended intosaid.

cylinder and connected to said piston whereby said needle valve ismovable with said piston, means for admitting fluid to saidcylindersonboth'. sides of said piston to effect movementv of. said;pistonandsaidneedle valve, a'secondcylinder; a piston in saidsecondcylinder, a device extended between said: cylinders and having means fortransmitting the movement of one of'said pistons to the other of saidpistons, means for. admitting :a'

fluid under pressure to the second cylindercto hold the piston thereinagainst movement in-one' direction wherebythe piston to which said stemis connected may be retained in positions-into which it is moved byfluid: admittedintothe first cylinder on: the side of the piston:therein whereat said stem is' connected, and means including a pilotvalve controlling fluid flow to both of said cylinders and regulatingmovement of said pistons.

'7. In a: steam turbine, a wheel'having b .ckets cylinder and connectedto said piston whereby' said needle valve is. movable with said piston,means for admitting fluid to said cylinder on both sides of said pistonto effect movement of said piston and said needle valve, a secondcylinder, a piston in said second cylinder, adevice extended betweensaidcylinders and having means for transmitting the movement or" one ofsaid pistons to the other of said pistons, means for admitting a fluidunder-pressure to the sec-- ond cylinder to hold the piston thereinagainst movement in one direction whereby the piston to which said stemis connected may. be retained in positions into which it is moved-byfluidadmitted into the first cylinder on the side of the piston thereinwhereat said. stem. is. connected; means including a pilot valvecontrollingfluid flow to both of said cylinders and regulating movementof said pistons, and meansresponsive-to operating conditions of theturbine for controlling the operation of said'pilot valvetoregulate'fluid flow to said cylinders.

8. In a steam turbine, a wheel having buckets thereon. a nozzle foremitting a jet of steam to the buckets on said wheel, a needle valve forsaid nozzle and shaped to'determine the expansion ratio of thenozzlewhen extended into the. inlet of said nozzle-and movable between closed:and wide open. positions: relative to said inlet.

and. into positionsintermediate. the; ciosccb ancla wide open positionsacylinder, a: pistonini said; cylinder; said needle valve including-a;stem-extended into said cylinder'and' connected: to said, piston wherebysaid needle valve is movable with said piston, means for admitting fluidto said cylinder on both. sides of said: piston to effect movement ofsaid piston and said needle valve; means cooperating with saidp-istonon. the side thereof opposite to that whereat said. stem isconnected and adapted to. retain said piston in positions into which itis moved by fluidiadmitted into said cylinder on the side of said pistonwhereat said stem is connected, and means responsive to operatingconditions of the turbine and controlling fluid admission to saidcylinder to reg.-

.late the position of the piston therein and the position of said needlevalve relative to said inlet.

9. In a steam turbine, a wheel having buckets thereon, a nozzle foremitting a jet of steam to the buckets on saidwheel, a needle valve forsaid nozzle and shaped to determine the expansion ratio of the nozzlewhenextended into the inlet oi? said nozzle and movable between closedand wide open positions relative to said inlet and into positionsintermediate the closed and wide open positions, a cylinder, a piston insaid cylinder, said needle valve including a stem extended into saidcylinder and connected to said piston whereby said needle valve ismovable with said piston, means for admitting fluid to said cylinder onboth sides of said piston to effect movement of said piston and saidneedle valve, a second cylinder, a piston in saidsecond cylinder, adeviceextended between said cylinders and having means for transmittingthe movement of one of said pistons to the other of said pistons, means.for admitting a fluid under pressure tothe second cylinder to hold thepiston therein against movement in one direction whereby the piston towhich: saidstem iszconnected maybe retained inpositions into which it ismoved by fluid-admitted'into the first cylinder on the side of thepiston therein whereat said stem is connected, means including apiiotvalve-controlling fluidrflow. to both ofsaid-s cylinders and regulatingvmovement ofsaid pistons, and means responsive to'operating conditions ofthe turbine for; controlling, the operation of said pilot valve-toregulatefluid flow. to said, cylinders, said means responsive to theoperating conditions of the turbine including a'movable member connectedto the piston in thesecond cylinder, a member connected to saidpilotvalve and having a slot therein, means on saidlmovable memberdisposed in. said slot tobe movable therealong, and means. connectingthemovable member to a device actuated by operating. conditions-of theturbine whereby actuation of said device moves said pilot valvewhereupon movement eithe piston in the second'cylinder is effected andthe movable member is moved with said-piston to move the meansthereonin-said slot along said slot to move the pilot valve back intothe position in which it was'disposed prior tomovement thereof uponactuation of the'deviceresponsive to operating. conditions of theturbine.

10. Ina-steam. turbine, awheel'having buckets thereonpa, nozzle .ior.emitting a jet of steam to the buckets on. saidwheel, .a needle valvefor said nozzle and; shaped to determine the expansion. ratioofthe'nozzlewhen extended into theinlet of said nozzle: and movablebetween closed and wide open positions relative tosaidLinlet. and intopositions intermediate the closed and wideopen positions, a cylinder, apiston in said cylinder, said needle valve including a stem extendedinto said cylinder and connected to said piston whereby said needlevalve is movable with said piston, means for admitting fluid to saidcylinder on both sides of said piston to efiect movement of said pistonand said needle valve, a second cylinder, a piston in said secondcylinder, a device extended between said cylinders and having means fortransmitting the movement of one of said pistons to the other of saidpistons, means for admitting a fluid under pressure to the secondcylinder to hold the piston therein against movement in one directionwhereby the piston to which said stem is connected may be retained inpositions into which it is moved by fluid admitted into the firstcylinder on the side of the piston therein whereat said stem isconnected, means including a pilot valve controlling fluid flow to bothof said cylinders and regulating movement of said pistons, and meansresponsive to operating conditions of the turbine for controlling theoperation of said pilot valve to regulate fluid flow to said cylinders,said means'responsive to the operating conditions of the turbineincluding a device actuated by changes in the operating conditions, alink connected to said device to be movable'thereby, a bell crank lever,means connecting the bell crank lever to the piston in the secondcylinder, means connecting the bell crank lever to said link, said pilotvalve including a part having a slot therein, means on the bell cranklever movable along said slot, movement of said link moving said bellcrank lever to move the pilot valve to admit fluid at least to thesecond cylinder to move the piston therein and movement of the piston inthe second cylinder moving said bell crank to move the means thereon insaid slot along said slot to thereby move the pilot valve back into theposition in which it was disposed prior to movement of said link.

' JOSEF Y. DAHLSTRAND.

